scope:

Description of Driving Event:

In Building 30 at the Johnson Space Center, a contractor electrician received an electrical shock to the hand and forearm from contacting an energized (480 volt AC) power panel lug. A separate contractor, from a remote location that contained the control devices for the power panel, had switched off, tagged, and verified all circuits deenergized. An electrical drawing was used to assure all circuits were included in the safing procedure. However, a modification was performed earlier to add a lug set and wiring to the panel that was not routed through the same remote controls location as the original wires, and was not reflected on the facility master drawing. The injured electrician did not verify the lug was deenergized by testing with a meter or other device. The injury was minor (small entrance and exit burns), but could have resulted in severe injury or death had the current passed through the torso. Corrective actions included updating the facility drawings and emphasis on enforcement of existing procedures for testing circuits as part of the lockout/tagout process.